By watching these measurements, you can learn how to alter these functions by relaxing or by holding pleasant images in your mind.

Electrodes measure your heart rate, blood pressure, or other function. A monitor displays the results for both you and the trained practitioner to see. A tone or other sound may be used to let you know when you've reached a goal or certain state.

While the practitioner describes stressful situations and guides you through relaxation techniques, you can see how your heart rate and blood pressure change in response to being stressed or remaining relaxed.

Biofeedback teaches you how to control and change these bodily functions. By doing so, you feel more relaxed and may be able to help treat such conditions as:

Anxiety and insomnia (how well biofeedback works for these symptoms remains controversial)

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